This commit makes LibRegex (mostly) capable of operating on any of
the three main string views:
- StringView for raw strings
- Utf8View for utf-8 encoded strings
- Utf32View for raw unicode strings
As a result, regexps with unicode strings should be able to properly
handle utf-8 and not stop in the middle of a code point.
A future commit will update LibJS to use the correct type of string
depending on the flags.
The C interface (posix interface?) for regexes has no "initialize"
function, only a free function. The comment in regcomp in
LibRegex/C/Regex.cpp notes that calling regcomp without a regfree is an
error, and will leak memory. Every single time regcomp is called on a
regex_t*, it will allocate new memory.
Make sure that all the regcomp calls are paired with a regfree in the
tests program
